1. Field of the Invention
This invention relates to structure of a flat display panel and a method of manufacturing the flat display panel.
The present application claims priority from Japanese Application No. 2002-167073, the disclosure of which is incorporated herein by reference.
2. Description of the Related Art
In the manufacturing process for flat display panels which cause light emission in the space defined between two substrates for generation of a display image, such as plasma display panels (hereinafter referred to as “PDP”), field emission display (FED) panels and the like, a process for exhausting air from the space between the two substrates is typically required in order to produce a vacuum inside the space defined between the two substrates in which light emission is carried out, and/or to keep the space in the state of being filled with a discharge gas.
FIG. 1 illustrates a conventional structure for exhausting air from the space between the two substrates of such a flat display panel.
FIG. 1 shows a front glass substrate 1 constituting the display screen of the flat display panel, and a back glass substrate 2 constituting the back part of the flat display panel.
The flat display panel has the front glass substrate 1 and the back glass substrate 2 facing each other at a predetermined interval. A space S thus defined between the glass substrates 1 and 2 is sealed by a sealing layer 3 formed on the peripheral edge between the front glass substrate 1 and the back glass substrate 2.
A ventilation hole 2A is formed for establishing communication between the space S and the outside in a position on the inner portion of the back glass substrate 2 close to the sealing layer 3.
A ventilation duct 4 is placed coaxially with the ventilation hole 2A on the outside surface of the back glass substrate 2. A seal between an end of the ventilation duct 4 and the ventilation hole 2A is provided by a pressed frit 5. The pressed frit 5 is made of a frit paste (sealing materials) essentially consisting of low-melting glass powders, and formed around the opening of the ventilation hole 2A on the back glass substrate 2.
In the prior art, as illustrated in FIG. 1, the flat display panel with the front glass substrate 1 facing downward is supported from beneath by supporting arms M, and then the ventilation duct 4 is mounted on the back glass substrate 2 from above.
Then, the exhaustion of air from the space S formed between the front glass substrate 1 and the back glass substrate 2, and the infusion of the discharge gas into the space S in the case of PDPs, are carried out via the ventilation hole 2A from the ventilation duct 4 mounted on the back glass substrate 2 as described above. After completion of the exhaustion of air and/or the infusion of the discharge gas, the opening of the ventilation duct 4 is sealed to make the space S airtight.
As described above, the flat display panel is supported with the front glass substrate 1 facing downward and the ventilation duct 4 is mounted on the back glass substrate 2 from above. This is because of prevention of imperfect attaching and sealing. If the ventilation duct 4 is mounted on the back glass substrate 2 from beneath while the flat display panel with the back glass substrate 2 facing downward is supported, in the process of forming the pressed frit 5 between the end of the ventilation duct 4 and the ventilation hole 2A by use of the frit paste, the frit paste may run to other unrelated parts and adhere thereto, and the pressed frit 5 may not be formed in a predetermined shape, leading to the imperfect attaching and sealing.
However, the fact that the front glass substrate 1 is placed so that its front surface points downward and supported by the supported arms M in the process of mounting the ventilation duct 4 on the back glass substrate 2 as done in the foregoing conventional manufacturing method, gives rise to the problem of producing scratches or stains on the front glass substrate 1 which serves as the display screen for images.